---
name: "otp"
section: "3tcl"
platform: "linux"
package: "tcllib"
version: "2.0+dfsg-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/otp/3tcl"
---

# otp(3tcl)

One-Time Passwords

```

```

## NAME

otp - One-Time Passwords

## SYNOPSIS

package require **Tcl 8.5 9**

package require **otp ?1.1.0?**

**::otp::otp-md4** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

**::otp::otp-md5** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

**::otp::otp-sha1** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

**::otp::otp-rmd160** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

```

```

## DESCRIPTION

This package is an implementation in Tcl of the One-Time Password system as described in RFC 2289 (1). This system uses message-digest algorithms to sequentially hash a passphrase to create single-use passwords. The resulting data is then provided to the user as either hexadecimal digits or encoded using a dictionary of 2048 words. This system is used by OpenBSD for secure login and can be used as a SASL mechanism for authenticating users.

In this implementation we provide support for four algorithms that are included in the tcllib distribution: MD5 (2), MD4 (3), RIPE-MD160 (4) and SHA-1 (5).

## COMMANDS

- **::otp::otp-md4** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

  - **::otp::otp-md5** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

  - **::otp::otp-sha1** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

  - **::otp::otp-rmd160** ?*-hex*? ?*-words*? *-seed seed* *-count count* *data*

  ## EXAMPLES

```
% otp::otp-md5 -count 99 -seed host67821 "My Secret Pass Phrase"
(binary gibberish)
% otp::otp-md5 -words -count 99 -seed host67821 "My Secret Pass Phrase"
SOON ARAB BURG LIMB FILE WAD
% otp::otp-md5 -hex -count 99 -seed host67821 "My Secret Pass Phrase"
e249b58257c80087
```

## REFERENCES

- \[1\]

  Haller, N. et al., "A One-Time Password System", RFC 2289, February 1998. *http://www.rfc-editor.org/rfc/rfc2289.txt*

- \[2\]

  Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, MIT and RSA Data Security, Inc, April 1992. (*http://www.rfc-editor.org/rfc/rfc1321.txt*)

- \[3\]

  Rivest, R., "The MD4 Message Digest Algorithm", RFC 1320, MIT, April 1992. (*http://www.rfc-editor.org/rfc/rfc1320.txt*)

- \[4\]

  H. Dobbertin, A. Bosselaers, B. Preneel, "RIPEMD-160, a strengthened version of RIPEMD" *http://www.esat.kuleuven.ac.be/~cosicart/pdf/AB-9601/AB-9601.pdf*

- \[5\]

  "Secure Hash Standard", National Institute of Standards and Technology, U.S. Department Of Commerce, April 1995. (*http://www.itl.nist.gov/fipspubs/fip180-1.htm*)

## BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category *otp* of the *Tcllib Trackers* \[http://core.tcl.tk/tcllib/reportlist\]. Please also report any ideas for enhancements you may have for either package and/or documentation.

When proposing code changes, please provide *unified diffs*, i.e the output of **diff -u**.

Note further that *attachments* are strongly preferred over inlined patches. Attachments can be made by going to the **Edit** form of the ticket immediately after its creation, and then using the left-most button in the secondary navigation bar.

## SEE ALSO

SASL, md4, md5, ripemd160, sha1

## KEYWORDS

hashing, message-digest, password, rfc 2289, security

## CATEGORY

Hashes, checksums, and encryption

## COPYRIGHT

```
Copyright (c) 2006, Pat Thoyts <patthoyts@users.sourceforge.net>
```